Nystatin: Nystatin is a fungistatic and fungicidal polyene antibiotic, which increases the permeability of the cell membrane of sensitive fungi by binding to sterols, chiefly ergosterol. Its main action is against Candida species. It is also effective against Aspergillus, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum, Blastomyces dermatidis, and other yeasts and fungi. Nystatin has been used to enrich mutants by killing yeast cells. Nystatin has no antibacterial activity. The minimum inhibitory concentration for most sensitive fungi has been reported to range from 1.56 to 6.25 μg/ml. Nystatin is poorly absorbed from the gastrointestinal tract. It is not absorbed through the skin or mucous membranes when applied topically.